loneliness

Hei y'all,
I could really use some advice. I am currently in my senior year of hs, so I will be going to university next year. I have recently been dealing with extreme loneliness. Ever since my freshman year, I've been really close with this friend but she is really shy. I was also part of this bigger friend group and I used to make sure that my friend would also get invitied because I knew she was having a hard time making friends. Now, 5 years later (im not from the US so my schooling system is different), I am still part of this friendgroup. However, my friend has been socializing more and gotten less shy. Dont get me wrong, I am happy for her but we are starting to grow apart. This friendgroup we are part of is toxic. I know its not a nice thing to say but its the truth. They have been cutting me out, not inviting me to parties, keeping plans they made from me and they have now reached the point where they are going on a vacation without me, and im the only one not invited. I had this other really really close best friend but she moved abroad last year... I do still have a lot of contact with her tho. Last summer I started getting closer to this other girl in this friendgroup and we are getting along really well. Due to quarantine, I have realized that I dont like my friendgroup and I cannot wait to cut them out of my life once i go to uni. There is also this new, relatively small, friendgroup in my year (they are new) and I get along really well with them because we think the same way and we like the same things; which i do not have with that other friendgroup. So, I need advice on two things: how do i deal with constantly being left out and ignored? I am having a really really tough time. And secondly, I dont want to hang out with this friendgroup anymore. Should i take the risk and start hanging out with that new, smaller friendgroup whom I really like and risk ending up with nobody. Or should I just get through the year and leave this 'friendgroup' once I finish hs? Oh and btw that new friendgroup is already really close and they also have friends from outside of school that are part of that group so it might be hard to involve myself with them.
Respect to you if you have made it this far into my story Thank you so much if you took the time to read this! I could really really use your advice because my mind has been in a really dark place lately and i have no one to talk to.
Thank you so so much
xx